Editor's Summary
27 August 2009
Hot Jupiter WASP-18b: a too-close encounter
'Hot Jupiter' extrasolar planets are thought to have formed at some distance from their host stars and to have migrated inwards at a later date. These planets provide new perspectives on the evolution of planetary systems, and the discovery of WASP-18b, the closest-orbiting and most extreme hot Jupiter yet, provides a glimpse of what may be a planet nearing the end of its life. With a close orbit, high mass (ten times that of Jupiter), and brief (0.94-day) orbital period, WASP-18b has the strongest tidal interaction of any known star–planet system. We appear to be seeing WASP-18b in a rare and short-lived state as it spirals towards its host star, destined to be destroyed within the host star's lifetime. Alternatively, the tidal dissipation this system — and perhaps other hot Jupiters — must be much weaker than that in our Solar System.
News and Views: Extrasolar planets: Secrets that only tides will tell
Evidence that the most recently discovered extrasolar planet is virtually at the end of its life is a surprise. The odds of that are very low — similar to drawing two consecutive red aces from a well-shuffled deck of cards.
Douglas P. Hamilton
doi:10.1038/4601086a
Letter: An orbital period of 0.94 days for the hot-Jupiter planet WASP-18b
Coel Hellier, D. R. Anderson, A. Collier Cameron, M. Gillon, L. Hebb, P. F. L. Maxted, D. Queloz, B. Smalley, A. H. M. J. Triaud, R. G. West, D. M. Wilson, S. J. Bentley, B. Enoch, K. Horne, J. Irwin, T. A. Lister, M. Mayor, N. Parley, F. Pepe, D. L. Pollacco, D. Segransan, S. Udry & P. J. Wheatley
doi:10.1038/nature08245
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